In this work the interfacial mass transfer of the system water-toluene with four different transferring components (acetone, ethanol, tetrahydrofuran, and acetonitrile) was examined. For this the liquid-liquid equilibria, the interfacial tension, and the mass transfer across the interface of these systems were experimentally determined. On the basis of this experimental data, the theoretical framework, which is based on the Koningsveld-Kleintjens approach and the concentration gradient theory, was parametrized. With the use of the Koningsveld-Kleintjens approach, the liquid-liquid equilibria were modeled and the concentration gradient theory was applied to model the interfacial properties in equilibrium as well as in nonequilibrium. It was shown that the concentration gradient theory in combination with the Koningsveld-Kleintjens approach could be used to model the mass transfer across the interface. Further, a connection between the enrichment of the transferring component at the interface and the time to equilibrate the system was found.